Part III: Slot Machine Cheating · Physical Cheating Methods · #5.2

Shaved Coins

How it works

When casinos introduced optic verification sensors to defeat yo-yo cheating, cheats developed an ingenious workaround. By lightly shaving the edges of a coin, they could exploit the fact that the optic sensor and the physical weight comparator often worked independently. The shaved coin would pass the optic sensor and register a credit, but when it reached the weight comparator mechanism, the slight weight discrepancy would cause the machine to reject it and eject the coin. This allowed cheats to get the credit without losing the coin – essentially the yo-yo scam without any string.

Where it appears

Coin-operated slot machines with separate optic sensors and physical comparators.

On the record

This scam emerged in direct response to casinos adding optic verification sensors. The technology designed to prevent yo-yo cheating inadvertently created a new vulnerability that shaved coins exploited.

Published as a detection reference for surveillance, compliance and gaming-operations professionals. Thresholds and tuning are set by the property. Nothing here is instruction — the method is described so it can be recognised.